My bunny loves any hanging toy. He also loves tunnels a good tunnel is a cat tunnel from the dollar store. He also loves hay and wooden stick balls with bells or stuff inside them. He’s not to fond of wood, or paper towel rolls which sucks since there cheap.

Litter box is probably the way to go, especially once you add the play pen on. Since he likes to rip up the fabric, seems like he likes to shred and dig! You can try phone books, newspaper stuffed in paper towel tubes, or just plain old cardboard boxes. If you turn the box into a hideout by cutting a few holes in the sides, he may like to “remodel” it. You can also stuff a box with paper and let him tunnel and shred inside. Try hiding his pellets in the paper to make it more fun for him. Mine also like to reshape and “dig” at cardboard cat scratchers. Animals play in ways that help exercise instinctive behaviors, so for bunnies that is often digging and chewing, which means the best toys are often cheap or free.  

Fleece blankets can also be “dug” in and pushed around, even if it’s hot he may still enjoy pushing them around, just make sure he’s not actually eating them. 

Mine also like to chew willow branches, and MUCH prefer fresh ones over store bought. 

You might also see if he likes noisy toys. Mine love throwing around a tiny cowbell, and also would play “catch” with cat “batta balls” with the little bell in them (but I only let them play with those when supervised).